Aneroid barometer.



N0 MODEL.

PATENTED JUNE 28, 1904. F. E- OOLLINSON.

ANEROID B AROMETER. APPLIUATION FILED 0015, 190a.

F |cT-Z. WITNESSES;

INVENTCIR WUNETIEEJJ Patented June 28, 1904.

Farmer @rrrcre.

ANEFiOlD BAHQNIETER'.

SPECIFICATION forming part of Letters Patent No. 763,659, dated June 28, 1904.

Application filed October 5,1903. Serial 179- 175,866. (No model.)

T 0 (all whom it may concern.-

Beit known that I, FRANCIS E. Connmsou, a citizen of the United States, residing at Wakefield, in the county of Middlesex and State of Massachusetts, have invented a new and useful Improvement in Aneroid Baroinet ers, of

which the following, taken in Connection with the/accompanying drawings, is a specification. .My invention relates to an indicating device to be added to an ordinary aneroid barometer, by the aid of which the correct weather reading may beindicated for any given elevation; and it consists in connecting with the pressure-indicating hand of a barometer an auxiliary hand moving with the said pressurehand, which may be set at such an angle with it as to point to the correct weather reading for the determined elevation.

. To illustrate by example, an ordinary aneroid barometer has a single pointing-hand, which indicates the atmospheric pressure only, and around the dial the weather readings are arranged thusrAt the number 30, indicat-\ ingthe pressure, he Weather reading isFair, and at the number 29 the weather reading is Rain. These, as well as the other weather readings, are correct only when the observer is using the instrument at about fifty feet above the sea-level, for the reason that at this elevation the atmospheric pressure is in fair Weather about 30-that is, the normal fairweather pressure for this level is 30; but this is not true for any other altitude. In fact, the normal fair-weather pressure de" creases rapidly as the altitude increases. For instance, at an altitude of about one thousand feet the fair-weather pressure is 29 and at the altitude of, about two thousand feet the.

fair-weather pressure is 28, and so on.

The object of the invention is to provide a convenient and inexpensive aneroid barometer that shallhave a weather-indicating hand adapted to be so adjusted as to indicate the probable weather for the known altitude.

This object I attain by means of the inecham ism shown in the accompanying drawings, in which Figure 1 news in elevation an ordinary aneroid barometer baring one of my weatherindicating hands attached. Figs. 2 and 3 are details illustrating manner of connecting the hands to the arbor of the aneroid.

In the drawings, A represents an aneroid barometer of ordinary construction, except that'it has an auxiliary hand. The arbor S of the aneroid is unchanged.

The hands of the aneroid -that is, the or dinary pressure-hand P and the weather-indicating hand W are both connected to the quill H. (See Fig. 3.) This quill is frictionally held to the arbor S, as usual, but is constructed in a peculiar manner, as will be explained. The body part H of the quill is made with a flange H and a neck H sure-indicating hand P is permanently attached to the flange H by its center disk P;

but the weather-indicating hand W may ormay not be rigidly attached. The quill has. a neck H to which the washer C and the screw-nut N are attached.

When the instrument is to be used in locations not much above the sea-level, the two The preshands P and W may coincide; but in case it at Fair, and. in case the elevation were two thousand feet the normal fair-weather pressure would be 28 of the dial, and the weather-hand W would have to be adjusted to stand at Fair. v

Having thus described my invention, What 1 claim as new, and desire to secure by Letters Patent, is

1. In an aneroid barometer the combination of a dial having weather remings and pres sure-graduations,apressure-hand and an aux; iliary hand adjustably attached to the pres-- sure-hand and moving with it, substantially as and for the purpose set forth. v

2. In an aneroid barorneterthe combination I withadial having weatherreadings and pres- I sure-graduations, ot a weather-hand, a pres sure-hand, a qu ll attached to the arbor and having a flange to which the pressure-hand is fixed, said flange having a. step portienof less width than the two hands and a screw-threaded neck portion to receive a nut and washer 5 whereby said Weather-hand is adapted to be adjustably attached to the pressure-hand.

In testimony whereof I have signed my name 7 to this specificatibn, in the presence of two subscribing witnesses, this 3d day of October, 

